1. Field of the Invention
The present invention relates to a medical device guidance system that has a position detection function of detecting the position of the medical device that passes in a gastrointestinal tract.
2. Description of the Related Art
In general, when a subject such as a patient is examined, an endoscope device that take images in the gastrointestinal tract as an image and performs monitor display is known as one medical device. Usually, an endoscope device is inserted from the oral cavity or the like and its tip has flexibility; lesions and the like to be observed are imaged by the imaging section installed on the tip side and the distal end side. A capsule endoscope is available that is different in its configuration from this capsule endoscope. The main body of this capsule endoscope, which is provided with an imaging element, is swallowed by a patient, and then passes through the gastrointestinal tract, to take image a desired target region. At this time, photograph the imaging range (angle of view) of the imaging section installed in the main body of the capsular endoscope is fixed, and thus the posture of the capsule main body needs to be controlled by guidance such that the desired target site is located within the imaging range. A system of controlling this posture involves applying a magnetic field generated from a coil installed in the surroundings, outside the body, to a magnetic field generated in the main body of a capsular endoscope, to thereby guide the main body or change the posture.
Such a guidance system is proposed, for example, in Jpn. Pat. Appln. KOKAI Publication No. 2006-026391. In this guidance system, the movement and posture are controlled by guidance field of a guidance coil arranged so as to enclose a medical device incorporating a magnet and a guidance coil by six faces. In addition, when a medical device take images a lesion or the like, its position needs to be specified. In this guidance system are disposed magnetic sensors at least in its three faces, and a position detection system, in which the position is detected by magnetic field generated from the medical device. This magnetic field sensor has arranged therein a large number of sense coils in each face for determining the position of the medical device from the magnetic intensity that each sense coil detects.